This invention relates generally to doors for the cargo areas of transport vehicles, for example, aircraft, and more particularly, relates to a powered, outwardly opening plug-type cargo door for an aircraft.
Outward-opening doors for use in cargo compartments of aircraft are advantageous compared to inward-opening doors in that they do not occupy volume in the cargo compartment that could otherwise be used for cargo. Plug-type doors for aircraft are advantageous over nonplug-type doors in that an adequate level of safety can be achieved with greater simplicity of mechanism by a plug-type door preventing the blowout or accidental opening of the door when the interior cargo compartment pressure is greater than the exterior ambient air pressure, for example, when the aircraft is in flight.
Previous outwardly opening plug-type cargo doors have been spring-couterbalanced and manually operated from the ground. A strut is used to prop the door open while cargo is being loaded and unloaded. The strut propping the door open prevents the door from inadvertently closing due to wind gusts or other external factors that would overcome the counterbalancing of the door. Also, the prior art doors, such as that used on the Boeing 727-200 aircraft include a snubber to control the speed of handle motion from the unlatched to latched position to avoid injury to the operator if the door handle were inadvertently started into the latching direction when the door was not in the cargo bay opening. In such a situation, the full weight of the door could backdrive the handle, injuring the operator if some mechanism were not provided to control the speed of handle motion. The snubber satisfactorily prevents operator injury but is a rather complicated mechanism that provides a source of potential maintenance problems and also additional weight to the aircraft.